Continuation rates of the subdermal contraceptive Implanon® and associated influencing factors

Objectives To investigate the continuation rates of the etonogestrel subdermal contraceptive implant among well-informed women, and the reasons for early discontinuation. Study design Retrospective consecutive cohort design. Methods Women who had the implant inserted between 1 January 2006 and 1 January 2010 at the Atrium Medical Centre, the Netherlands were followed up for at least three years. The dates of insertion and removal were recorded, as were the reasons for removal. Statistical analysis was performed using the independent samples t-test and the Pearson alpha correlation test. Results The implant was inserted in 230 women. Follow-up was possible in 214 women, with an average age of 26.7 years. Most of them were nulliparous and the majority had used a combined oral contraceptive, Implanon (R), or Mirena (R) previously. The mean overall continuation period was 23.5 months (95% confidence interval: 21.7-25.3), with a median of 25 months. The continuation rate after 12 months was 72%; after 24 months, 53%; and after 36 months, 25%, with all women concerned having a new implant placed. The previously used contraceptive method Implanon r was associated with the highest continuation rates. An erratic bleeding pattern was the main reason for early removal. Conclusions Despite adequate counselling before insertion, the continuation rate of the etonogestrel implant was rather low compared to those reported by other investigators. The main reason for discontinuation was an irregular bleeding pattern.